In 2845 Thráin II, King of Durin's folk-in-exile and holder of the last of the Seven Rings of the Dwarves, was imprisoned in Dol Guldur's dungeons. In 2850 Gandalf again entered Dol Guldur, finding the dying Thráin, and Gandalf was entrusted with the map and key to give to Thorin Oakenshield, although Thráin could not tell him his own or his son's name before he died. Gandalf confirmed Sauron was the master of Dol Guldur at that time.

Gandalf returned to the White Council and urged an attack on Dol Guldur, but was overruled by Saruman, who had begun searching for the One Ring in the area by then. In 2941 Saruman finally agreed to an attack, which occurred at the same time as the Quest of Erebor. This was carefully planned by Gandalf, so that Sauron and Smaug could not assist each other, as otherwise they surely would have done. Sauron fled to Mordor, his plans now ready. Dol Guldur remained staffed by the lieutenant of Barad-dûr.

During the War of the Ring, the forces of Dol Guldur made three assaults upon Lórien, causing grievous damage to the outlying woodlands, but were driven back each time by the power of Nenya which only Sauron himself could have overcome. Dol Guldur was finally destroyed and cleansed by the Elves of Lórien, led by Galadriel, after Sauron's fall. Named Amon Lanc once again, it became the capital of Celeborn's realm of East Lórien for a while.

Portrayal in Adaptations

Dol Guldur is commanded by the Mouth of Sauron, not Khamûl. Dol Guldur (or Mordor itself) sent a huge army of Orcs, Haradrim, and Trolls to assault Erebor. The attack fails, and the Mouth of Sauron is killed along with all the attacking force. Dol Guldur is then itself attacked by a combined army of Elves and Dwarves led by Elrond, Arwen, Glorfindel, Glóin, and Dáin Ironfoot. After a long and hard struggle, the Elves and Dwarves finally overrun Dol Guldur and lay waste to the evil that dwelled there, ending Sauron's war campaign in the North once and for all.

In the Evil Campaign, the Goblins from Dol Guldur eliminate the Elves and the Ents that guard the Forest Road in Mirkwood.